1. The state holiday in South Dakota called "Day of Reconciliation" is observed on December 6 every year. The holiday recognizes the efforts of the state's Native American tribes to reconcile with the state after a long history of mistreatment.

2. In 1980, the deadliest prison riot in US history occurred at the South Dakota State Penitentiary in Sioux Falls. The riot began on December 6 and lasted for two days, resulting in the deaths of two inmates and the injury of several others.

3. December 6, 1996, marked the opening of the Crazy Horse Memorial Museum in the Black Hills of South Dakota. The museum is dedicated to the life and work of Crazy Horse, a Lakota warrior who fought against the United States government's encroachment on Native American lands.

4. On December 6, 1883, the town of Aberdeen was officially incorporated. Located in northeastern South Dakota, Aberdeen has since become known as the "Hub City" due to its location at the intersection of two major highways.

5. South Dakota's first homegrown governor, Robert S. Vessey, was born on December 6, 1858. Vessey served as governor from 1909 to 1913 and was instrumental in expanding South Dakota's road infrastructure.